Has anyone got this library working on the new raspberry pi 5? I was getting a permission error accessing /dev/mem even when running as root. This is using the latest version of raspbian.
Is there something I need to do to get the permissions correct on rasbian or is it just no supported right now?
Henner mentions he won’t be able to get to it until at least the end of the year at the earliest. Rasberry Pi 5 support? · Issue #1603 · hzeller/rpi-rgb-led-matrix · GitHub
not your direct question, but do you really need an rPi3? Even the rPi4 is too fast and needs to be slowed down.
Basically anything beyond an rPi3 is too fast, too much computer, and you’re just wasting it slowing it down to match the panel speed that cannot keep up.
So unless you’re literally computing some complex real time 3D in CPU to render on the panels, I really recommend you simply get some cheaper and smaller rPi3a’s
Call me crazy, but feel that a pi4 can handle more pixels with more colors than a 3b.
Have you actually measured that?
Have you built a 384x256 display on 3 channels or something close to it, and hit limits where Rpi3 didn’t keep up?
It’s been 3+ years since I looked at it closely, but it always seemed that rPi3 did fine, and rPi4 had to be slowed down more and more or avoid display problems.
and while I’m interested in your 3 vs 4, results, my point that rPi5 is definitely way faster than needed for 3 channels, still stands until you prove me otherwise 
Thanks for sharing the article. Will give it a read.
I’ll compare the article’s implementation to my own.
However from my own implementation 20 (64x64 matrices), the Pi4s could only drive 4 panels with PWM LED bits set to 6, while the Pi3 required a value of 4.
So great to enter this discussion. I feel like I will learn a lot.
Maybe I am mistaken but I was thinking that the limit of number of panels was due to the speed at which you could push out pixels to the LED panels. For my project I would like to drive a large number of panels. Is my reasoning wrong here?
that is my understanding too and why I was doubting that rPi4 or rPi5 could drive any more panels on 3 channels since I’m pretty sure rPi3 can already output at full speed for each bus or close to it. If not we know rPi4 is too fast since it only works when you give it an option to slow it down. I’m kind of 100% sure that rPi5 can’t drive any more or any faster on 3 busses only. The only way to go faster is to have more busses.
Hi there, In my case, 3x4 P4 outdoor panels (256x96px) running on 3 channels with full color depth quality I get arround 400fps, limited to 300fps to avoid any blink /stutter when the Pi is running other things as this value goes up and down.
300 stable fps may sound like a lot, but they are far less than 1920fps (hz) recomended. This make impossible to take a picture of the screen on day light and also, if you quickly shake your head /eyes you see very weird things on the screen.
in brief, running just a 256px screen on a rPi4 I get ~20% fps of what it’s really needed, I wonder what do you mean with “too fast” as I might be wrong or am I misunderstanding concepts.
Just asking, in a good spirit
I’ve seen similar things than you and you are correct that 300Hz outdoors is not enough for pictures. The only thing you can do is to make sure you find panels that can take as quick a refresh rate as possible, lower the color depth,
Have a look at Marc's Blog: arduino - RGB Panels, from 192x80, to 384x192, to 384x256 and maybe not much beyond
for options